Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related death worldwide and the ninth leading cause in the US. According to the International agency for Research on Cancer, HCC is the fifth most common cancer in men (523,000 cases per year with 7.9% of all cancer cases) and the seventh most common cancer in women (226,000 cases per year with 6.5% of all cancer cases). For patients with lesions less than 2 cm, radiofrequency ablation (RFA) under ultrasound guidance is the recommended treatment.
RFA works by heating the tissue to hyperthermic levels for several minutes resulting in necrosis. Two weaknesses of this technique are the lack of a sharp boundary to the ablation zone and poor ablation around vessels and ducts. Since the spread of heat depends on the thermal conductivity of the tissue, it is difficult to control the precise boundary of this ablation zone. In addition, the presence of heat sinks such as large vessels or ducts allows heat to be carried away from the tissue near the vessel and makes it difficult to reach the temperature required to ablate tissues in those regions.